A new survey suggests that large data centers might be less energy efficient than was previously thought.
The survey, by Digital Realty Trust, quizzed 300 IT decision makers at large corporations in North America, each with annual revenue of at least US$1 billion or with at least 5,000 employees.
The results revealed an average PUE (Power Usage Effectiveness) score of 2.9. PUE is a measure of data center efficiency, and lower scores are better. Ideal scores are close to 1.0, and previous surveys have estimated the average to be closer to 2.0.
PUE is only one way of measuring energy efficiency and there’s no standardized way of calculating it, so the finding isn’t necessarily dire. But it’s a data point suggesting that data centers might be less efficient on average than previously thought.
The Uptime Institute, in a survey last year of 1,100 data center users, reported an average PUE of 1.8 to 1.89. That was an improvement over 2.5 in its 2007 survey. The U.S. Environmental Protection Agency, in 2009, reportedly put the average PUE at 1.91.
Big online firms such as Google and Microsoft have boasted of PUEs of close to 1.0, but they’re special cases. Many of the data centers they operate are new, and they invest heavily in IT efficiency, since it affects so much of their overall operating costs.
“While a PUE of 2.9 seems terribly inefficient, we view it as more being closer to the norm than the extremely low (close to 1) figures reported in the media,” said Jim Smith, Digital Realty’s CTO, via email. “In our view, those figures represent what a very small number of organizations can achieve based on a unique operating model.”
The survey also showed that 20 percent of respondents reported having a PUE of less than 2.0, while 9 percent had a PUE of 4.0 or greater.
——- See the full report online at Network World